1. Field of the Invention
The present invention relates to soil heat exchanger for effecting an energy exchange between earth soil and an energy exchanger and including a thermoinsulated supply flow duct arranged in a borehole formed in ground, a pump provided at an end of the supply flow duct; a shroud pipe surrounding the supply flow duct and the pump and having a plurality of inlet openings, and a return flow region for return water located radially outwardly of the shroud pipe and including return flow pipes connectable with the energy exchanger, and a porous filling, with the return flow pipes extending up to a bottom of the borehole and having lateral openings communicating with an interior of the shroud pipe through the inlet openings of the shroud pipe.
2. Description of the Prior Art
Apparatuses or heat exchangers of the above-described type are generally known, and one is disclosed in European Patent No. 0386176. Such an open, i.e., pressureless system, in which the supply flow conduit and the return flow conduit do not form any closed conduit system, has proved itself to be very good. However, when such an apparatus is used in a soil with loose geological layers or when the water is contaminated with impurities, there exists a danger that the inlet openings of the shroud pipe become blocked, and the circulation of return water with the delivery water is not possible any more or at least is accomplished with much difficulty.
Accordingly, an object of the invention is a soil heat exchanger of the above-described type in which the water circulation is reliably assured.